Soap (2 bars Clearly Natural Glycerin)
Washing Soda (1/2 cup, not baking soda)
Borax (1/2 cup)
5 gallon bucket
Dissolve soap in saucepan (some soaps will need to be grated first), stir in washing soda and borax. Stir until thickened, remove. Add 1 quart hot water to bucket, add soap mix. Stir well. Fill bucket with hot water. Mix well. Let it sit for 24 hours to thicken. (you can use it sooner) Use 1/2 cup per load.
Note: there is a lot of room for variety in these recipes; I've used Dr B for the soap - you could really use any soap. Also, there are lots of versions - I've seen this recipe made in a 2 gallon bucket, instead of a 5. I believe I got this from The Queen of Clean website.